Project DC2’s K20 powerplant has been left internally untouched for the duration of this build because it’s been proven time and time again that it’s hard to beat the durability and reliability of Honda engineering. My engine has lived a hard life, logging mostly track miles and (knock on wood) has yet to show any signs of failure.
When the opportunity arose to add some aftermarket camshafts, I was a bit hesitant since I really didn’t want to mess with a good thing, but with SportCar Motion providing me free service (thanks, Loi and gang!) and Kelford supplying me with its Stage 1 camshafts that require no valvetrain modifications, I figured it couldn’t hurt to get a bump in power.
I’ve known about Kelford cams from the Mitsubishi EVO world, where they have a reputation for delivering great reliability and excellent power gains. I knew I was in good hands with the New Zealand–based company and wouldn’t have to worry about driveability issues or quality-control problems, as have been the case with some aftermarket cam manufacturers these days. Aside from being able to work with the factory Honda valvetrain, the Stage 1 cams’ primary and intermediate lobes are slightly larger than those of the OE TSX cams found in K24 engines, meaning you can expect some modest power gains while still being very streetable.
After SportCar Motion was done installing the cams, I headed over to Church Automotive Testing to have my tune tweaked and remapped for the Kelford Stage 1 cams. As usual, Sean Church made it look easy, as he always does when tuning my engine, and within an hour had the K20 running beautifully, producing 235 whp and 175 ft-lbs of torque. The last time the Integra was on the dyno (with stock camshafts) it produced 228 whp and 170 ft-lbs of torque — a gain of 7 whp and 5 ft-lbs. Not bad, but we had hoped for a bit more.
After poking around in the Hondata software, Sean noticed that the intake temperatures were getting rather high, which was affecting power output; our short ram intake was the culprit. He quickly fitted one of Church’s long-tube intakes and positioned it up and away from the engine. The motor loved the cooler intake charge and rewarded us with 241 whp and 184 ft-lbs of torque. In total, the Kelford cams picked up 13 whp and 14 ft-lbs with the fresh air. Technically, we should have dyno’d the stock cams with the same intake setup, but there wasn’t enough time to do that before this article.
The numbers don’t tell the whole story, though — the Kelford cams definitely feel stronger in power delivery than their stock counterparts. As the revs climb, the power just keeps coming. Given more rpm, the Kelford cams would keep making even more power, whereas the stock cams seem to peak at 7800 rpm. I had my rev limiter set to 8000 rpm to keep it on the safe side considering the more aggressive profile of the Kelford cams. They can safely rev to 8500 rpm on the stock valvetrain, but because this engine sees prolonged periods of high rpm at the track, I’d rather play it safe. With aftermarket valvetrain and more modifications, I’m willing to bet these cams will make even more power than with my pretty basic setup.
Shortly after the camshaft install, I was getting ready for a track day when I noticed a rather significant vibration in the drivetrain that would worsen as I applied the throttle. The first thing I did was have the wheels balanced, but nothing improved. It was only upon further inspection underneath the vehicle that I realized the driveshafts were worn and had excessive play. I quickly called upon Hasport for a set of its K-series axles. These axles are built tougher than their stock counterparts and can handle a lot more abuse, which I intend to put them through.
As usual, I’m never content doing one job; I always end up adding more parts to my to-do list to maximize my day in the garage, so orders went out for a Toda baffled oil pan, timing chain and tensioner, and an AEM cold-air intake.
The Toda Anti G-Force baffled oil pan was a must do on my list, as the stock oil pan has no baffling, and during high-load corners can starve the engine oil pickup, resulting in a spun bearing or, worse, catastrophic engine damage. The plate that Toda welds into its oil pan prevents the oil from sloshing up the sides of the pan, ensuring the oil pickup is always fed with oil. Toda also welds an extra threaded bung in the pan for easy oil temperature or pressure-sender mounting.
I also decided that it would be in my best interest to replace the OEM timing chain and tensioner with Toda units that have been specifically designed to deal with the added stresses of higher-lift camshafts. The heavy-duty timing chain has improved on Honda’s design by increasing chain strength and reducing edge burrs for smoother chain operation. Toda’s tensioner also improves on a weak OEM design that’s prone to failure under high-stress operation, especially with aftermarket camshafts present. With these two items, you should never have to worry about a timing failure. The only drawback to these parts is the installation process, which, in my case, forced me to practically pull the engine out of bay. There’s very little room on the timing side of the K20/DC2 setup, so dropping the motor is a must. I’d recommend leaving this to a professional.
Thankfully, the AEM hybrid cold-air intake was an easy install. After seeing how much I would benefit from a cold-air intake on the dyno, it was a no-brainer to install the AEM intake, which mounts in the driver-side fenderwell away from any hot air. I had to get creative and build a smaller windshield-washer-fluid reservoir out of a plastic bottle since the factory one was way too big and collided with the air filter.
The day that I was about to finish everything and get the car running, yet another part found its way onto my desk and into the DC2’s engine bay. Nippon Thermostat, which supplies more than 50 percent of Japan’s thermostats to OE car manufacturers, had sent me one of its new Low Temperature Sports Thermostats that opens at a lower engine temperature (160 degrees Fahrenheit) than the stock one, allowing the radiator to do its job sooner and, ultimately, reducing engine operating temperatures.
At this point, I’ve checked off quite a lot of to-dos on Project DC2, and what better way to reward myself than put it back on the track and see how well it performs. Much like my EVO X, maybe it too can start inching closer to that elusive 2-minute time barrier at Buttonwillow Raceway Park.
Stage 1 K20A Cams
Anti G-Force Oil Pan, Heavy-duty Timing Chain & Tensioner
Hybrid Cold-air Intake
K20A Low Temperature Sports Thermostat